Users of computers need to navigate within data rich environments in order to access relevant information.
Referring now to FIG. 1, there is shown a PRIOR ART personal computer system (PCS) which includes a software system 11, at least one output device 12 and at least one input device 14.
The software system 11 includes an information extractor 111 which is configured to obtain data from an information source 10. Extracted data is processed by an output generator 112 and sent to the output devices, shown in block 12. The output devices typically provide a visual representation of the data to a user 13 via a visual display unit (VDU) 122. Supplementary output may be provided by an audio output device 121, such as a speaker. Input devices 14, which may be keyboards, computer mice, touch pads, joysticks and the like, are devices configured to allow the user 13 to provide feedback 13 to the software system 11.
A sighted user will typically navigate using the PCS system by observing the visual information provided by the VDU 122 and providing feedback 113 for selecting pertinent data. For example, a cursor may be indicated upon the VDU, the position of the cursor may be adjusted by a user manipulating a keyboard, mouse or other input device 14, which may then be used to select a desirable portion of the information displayed.
A visually impaired user is not able to use the visual indications provided by the PCS, and there is thus a need to facilitate access and navigation by non-visual means.
It will be appreciated that the above-described prior art PCS (FIG. 1) which is dependent solely upon visual output devices 122, is not appropriate for use by a visually impaired user.
Referring now to FIG. 2, there is shown a block diagram representing the main components of a further, enhanced PRIOR ART PCS similar to that of FIG. 1, but also including accessibility and navigation aids for the visually impaired.
The enhanced PCS includes a number of elements not included in the PCS shown and described above in conjunction with FIG. 1, specifically a Refreshable Braille Display (RBD) 123, whose main function is the tactile display of Braille symbols. RBD 123 may further include command controls for moving the text line up and down and for controlling the position along the line and as such also functions as an input device.
In the system shown in FIG. 2, software system 11 is seen to include some additional elements, including a screen reader 114 and a generator of accessible information (GAI) 115, which are used to render the visual data presentation into a form that may be presented to a blind user via speakers 121 and/or by RBD 123.
The screen reader 114 is configured to extract and analyze all information presented in the VDU 122, including graphic and textual information, as well as information regarding GUI elements. The screen reader 114 is further adapted to receive user feedback 116 from the input units including those associated with RBD 123. The GAI 115 processes the data from the screen reader 114 and outputs the data to the user using VDU 122, speakers 121 and RBD 123.
FIGS. 3A and 3B represent the feedback of data for the prior art PCS systems of FIGS. 1 and 2, respectively. With particular reference to FIGS. 1 and 3A, data obtained by the information extractor 111 from the information source is transferred to the output generator 112, from where it is provided to VDU 122 for presentation to the user 13. The user 13 provides feedback to the information extractor 111 using input devices 14 such as a keyboard or a mouse. In response to user feedback, the information extractor 111 may obtain further information from the source.
FIG. 3B shows the corresponding feedback cycle associated with the PCS system of FIG. 2, thus requiring an additional feedback loop, as shown. The visual display 122 is analyzed by the screen reader 114 which provides data to RBD 123 via the output generator 112, as well as to VDU 122. The user 13, upon receiving information from RBD 123 may provide feedback, via input devices 14, to either the information extractor 111 or to the screen reader 114.
The enhanced PCS allows a visually impaired user to navigate between GUI Elements (GEs) by providing access both to visual (name, caption, etc) and to non-visual (function, location, subordination, etc) descriptors. Such navigation is contextual in nature, meaning that the user navigates by referring to the context of the object under consideration without reference to its geometrical and spatial parameters (location, dimensions, overlapping, etc). Such navigation is referred to hereafter as Contextual Navigation (CN). It will be appreciated that contextual navigation is more limited than navigation used by sighted people which typically combines Contextual Navigating methods with Spatial Navigating methods.
The term Spatial Navigation refers to navigation using spatial indications such as the location of a target GUI element and the location of a mouse cursor which may be aligned by the user in order to select the target GUI. A sighted user will generally align a cursor to a GUI element by moving in a substantially straight line whilst correcting for deviations from that line along the way.
Tactile text output may incorporate elements of spatial navigation particularly for a user reading large amounts of text with an RBD. For example, a user may shift to the next symbol, search for the beginning of the current word, jump to the previous line and so on. However, prior art systems do not lend themselves to spatial navigation techniques requiring graphic perception; navigational actions such as following a line or a curve, moving to a top-left corner of a window, screen or dialog box, dragging and dropping and the like. While these techniques are employed very effectively by sighted people with the aid of a mouse, they are completely unavailable to the blind.
A visually impaired user typically uses a tactile output device such as an RBD to receive contextual information, and uses inputs such as the keyboard to provide feedback. This can be difficult to use as well as inefficient because of the necessity to learn hundreds of individual keyboard commands, and, because a visually impaired user has no access to visual guidance, even a skilled user learns to navigate successfully by using a process of trial and error, which may be very tiresome and discouraging. This is exacerbated in a system involving the use of an RBD, as the user's hands need to move repeatedly between the RBD and the keyboard and back, sometimes crossing over in the process.
Also known in the art is U.S. Pat. No. 5,912,660, entitled Mouse-Like Input/Output Device with Display Screen and Method for Its Use, the contents of which are incorporated herein by reference.